Course Of Chronic Myeloid Leukemia Research Articles

Risk factors determining adherence to tyrosine kinase inhibitors in chronic myeloid leukaemia.

Tyrosine kinase inhibitors (TKIs) have successfully changed the natural course of chronic myeloid leukaemia (CML). Although they are highly effective drugs, their clinical benefit is conditioned by adherence. This study aims to analyse the adherence of CML patients treated with TKIs and to identify the main factors influencing their adherence to TKIs treatment. An 8-month prospective, observational, multicentre study which included patients diagnosed with CML on treatment with TKIs attending the outpatient departments (OPD) of the Pharmacy Services of the participating hospitals. Adherence was assessed using two methods: the Simplified Medication Adherence Questionnaire (SMAQ) and the register of treatment dispensations from the OPDs. To analyse the predictors of adherence, a questionnaire was developed to report demographic and socio-economic information on the patients. A total of 130 patients enrolled in this study. Adherence rate was 56.9% (n = 74) among individuals, not conditioned by the type of drug used: imatinib (54.8%), nilotinib (63.6%) or dasatinib (54.3%) (p = 0.67). The patient educational level (p = 0.047) and employment status (p = 0.028) were predictors of non-adherence to treatment. Adherence is one of the most relevant parameters affecting the effectiveness of highly effective chronic treatments. Approximately half of our patients showed inadequate adherence to treatment with TKIs, with employment status and the individual's level of education emerging as the determining factors.

Chronic myeloid leukemia, tyrosine kinase inhibitors and cardiovascular system.

Cardiovascular system health becomes important with the extended survival of chronic myeloid leukemia (CML) patients. Cardiotoxicities are related to the second- and third-generation tyrosine kinase inhibitors (TKIs). The most frequent and important cardiovascular events are myocardial infarction, stroke and peripheral arterial disease, QT prolongation, pleural effusions, and both systemic and pulmonary hypertension. The aim of this paper is to review the interactions between administrated TKIs and the cardiovascular system during the clinical course of CML. Elucidation of TKI effects on the cardiovascular system is vital since the current goal of CML therapy is a cure that leads to normal age and gender-similar survival with a normal quality of life. Up to August 2022, literature searches were performed via the internet search engines MEDLINE, EMBASE, GOOGLE SCHOLAR: (i) chronic myeloid leukemia; (ii) tyrosine kinase inhibitor; (iii) cardiovascular system. Only articles in English and research including humans were included in the search. Tailored TKI treatment with individual patient characteristics must account for CML disease risk, patient age, patient comorbidities, patient compliance, TKI drug off-target risk profile, accelerated or blastic phase CML disease, pregnancy and allografting in CML. The treatment-free survival, improving quality of life, limiting adverse events of TKIs, and the optimal dose and administration duration of TKIs are still a matter of controversy. Special attention should be paid to the comorbidities of CML patients and clinical TKI effects on CVS since the aim of CML treatment is a cure that leads to normal age and gender-similar survival with a "normal" quality of life. CVS is an important morbidity and mortality cause for adult patients. The discontinuation of TKI treatment in CML and the treatment-free remission of CML patients are very important in order to reduce the risk for cardiovascular adverse effects of TKIs. The frail CML patients and especially the patients who have cardiac comorbidities, should be carefully evaluated for TKI treatment, and hematopoietic stem cell transplantation (HSCT) should be the last choice in these risky CML patients. The current CML treatment target is a cure that leads to normal age and gender-adjusted survival with a "normal" quality of life. Cardiovascular disorders are one of the major obstacles to reaching this target in CML patients. The treatment choices for CML patients must include a cardiovascular perspective.

Chronic Myeloid Leukemia, from Pathophysiology to Treatment-Free Remission: A Narrative Literature Review.

Chronic myeloid leukemia (CML) is one of the most common leukemias occurring in the adult population. The course of CML is divided into three phases: the chronic phase, the acceleration phase, and the blast phase. Pathophysiology of CML revolves around Philadelphia chromosome that constitutively activate tyrosine kinase through BCR-ABL1 oncoprotein. In the era of tyrosine kinase inhibitors (TKIs), CML patients now have a similar life expectancy to people without CML, and it is now very rare for CML patients to progress to the blast phase. Only a small proportion of CML patients have resistance to TKI, caused by BCR-ABL1 point mutations. CML patients with TKI resistance should be treated with second or third generation TKI, depending on the BCR-ABL1 mutation. Recently, many studies have shown that it is possible for CML patients who achieve a long-term deep molecular response to stop TKIs treatment and maintain remission. This review aimed to provide an overview of CML, including its pathophysiology, clinical manifestations, the role of stem cells, CML treatments, and treatment-free remission.

Rare and unfavorable course of chronic myeloid leukemia – a case report and review of the literature

Rare and unfavorable course of chronic myeloid leukemia – a case report and review of the literature

Cytogenetics-Based Risk Prediction of Blastic Transformation of CML Treated with Tyrosine Kinase Inhibitors

Background:Blast phase (BP) of chronic myeloid leukemia (CML) remains a major therapeutic challenge in the era of tyrosine kinase inhibitor (TKI) therapy. Given the lack of effective treatment for BP, a potential key to improve patient outcome lies in identifying patients at high risk of progression and preventing onset of BP. Additional chromosomal abnormalities (ACAs) are important determinants of patient outcome. Despite its rarity in TKI era, BP develops in most CML patients in pre-TKI era regardless of ACAs. It is unknown how the development of BP is differently affected by ACAs in the TKI era.Design:We investigated the value of ACAs in prediction of BP in a large cohort of CML patients. Inclusion criteria included: 1, received TKIs as part of therapy; 2, age at diagnosis > 18 years; 3, presence of t(9;22) or variant translocations detected by conventional karyotyping. All cytogenetic abnormalities in Ph+ cells except -Y were considered ACAs. We examined the latencies from initial CML diagnosis to ACA emergence (Interval 1), from ACA emergence to BP (Interval 2) and survival after BP (Interval 3).Results:A total of 2,326 patients were included in the study, including 1,322 men and 1,004 women with a median age at diagnosis of 49 years (range, 18-88 years). In total, 570 had ACAs, including 333 (58.4%) with a single ACA and 237 (41.5%) with multiple ACAs. The most common single ACAs were: +8, +Ph, 3q26.2 rearrangement, i(17q), and -7/7q-, with a frequency of 13.5%, 12.6%, 7.5%, 6.6%, 3.9%, respectively. Of 237 patients with complex ACAs, 18 had 3q26.2 rearrangement, 19 had -7/7q-, and 30 had i(17q) as a component of complex ACAs. Seven patients had two of these three ACAs in different combinations. These complex ACAs were grouped together as high-risk complex ACAs. Complex ACAs without these three chromosomal abnormalities were designated as other complex ACAs.Patients with 3q26.2 rearrangement, -7/7q-, i(17q) and high-risk complex ACAs had a significantly faster blastic transformation, with a median Interval 2 of 2.8, 0, 32.6, 0 months, respectively, compared with 19.2 months in patients with other complex ACAs, and unreached in patients with +8, +Ph, or other single ACAs, and (Fig 1A). Based on the frequency and velocity of blastic transformation, patients were stratified into four risk groups. Patients without ACA formed the standard-risk (SR) group, patients with isolated 3q26.2 rearrangement, -7/7q-, or i(17q) and high-risk complex ACAs formed the high-risk (HR) group, patients with +8, +Ph or other single ACAs formed the intermediate-1 risk (IR-1) group, and patients with other complex ACAs formed the intermediate-2 risk (IR-2) group. By risk group, the median Interval 2 was unreached for IR-1group, 19.2 months for IR-2 group, and 1.9 months for HR group. (Fig 1B), and the interval from CML diagnosis to BP (Interval 1 + Interval 2) was unreached for SR and IR-1, 83.7 months for IR-2 patients, and 58.2 months for HR patients (Fig 1C). This risk of BP correlated well with patient survival from CML diagnosis (Fig 1D).The disease course of CML patients with ACAs follows a triphasic course, that is, Interval 1, 2 and 3. There was no or little variation in Interval 1 among three ACA groups (Fig 1E). No significant difference in Interval 3 was observed among three ACA groups neither (Fig 1F). SR patients had only slightly better survival of 17.0 months, compared with 9.3 months in other 3 groups combined (Fig 1F). The lack of difference in Interval 1 and 3 indicate that the predominant determinant of CML disease course in TKI era lies in the duration of Interval 2, which is in turn highly ACA-dependent.Conclusions:Chromosomal alterations predict the risk of blastic transformation in CML patients treated with TKIs. Patients can be stratified into four different cytogenetic risk groups based on ACA-dependent risk of blastic transformation. This risk stratification highly correlates with patient survival. By prolonging the duration of Interval 2, TKI therapy mitigates the risk of blastic transformation associated with low-risk ACAs or no ACAs but does not alter the natural course of CML associated with high-risk ACAs: 3q26.2 rearrangement, -7/7q- and i(17q). Thus, we identify a group of patients who are at a high risk of rapid disease progression. These patients may benefit from alternative treatment approach including early allogeneic hematopoietic stem cell transplantation to prevent blastic transformation. [Display omitted] DisclosuresCortes:ARIAD: Consultancy, Research Funding; ImmunoGen: Consultancy, Research Funding; Teva: Research Funding; Novartis Pharmaceuticals Corporation: Consultancy, Research Funding; Sun Pharma: Research Funding; Pfizer: Consultancy, Research Funding; BMS: Consultancy, Research Funding. Kantarjian:Bristol-Meyers Squibb: Research Funding; Amgen: Research Funding; Pfizer: Research Funding; ARIAD: Research Funding; Novartis: Research Funding; Delta-Fly Pharma: Research Funding.

DNA Damage and DNA Damage Response in Chronic Myeloid Leukemia.

DNA damage and alterations in the DNA damage response (DDR) are critical sources of genetic instability that might be involved in BCR-ABL1 kinase-mediated blastic transformation of chronic myeloid leukemia (CML). Here, increased DNA damage is detected by γH2AX foci analysis in peripheral blood mononuclear cells (PBMCs) of de novo untreated chronic phase (CP)-CML patients (n = 5; 2.5 γH2AX foci per PBMC ± 0.5) and blast phase (BP)-CML patients (n = 3; 4.4 γH2AX foci per PBMC ± 0.7) as well as CP-CML patients with loss of major molecular response (MMR) (n = 5; 1.8 γH2AX foci per PBMC ± 0.4) when compared to DNA damage in PBMC of healthy donors (n = 8; 1.0 γH2AX foci per PBMC ± 0.1) and CP-CML patients in deep molecular response or MMR (n = 26; 1.0 γH2AX foci per PBMC ± 0.1). Progressive activation of erroneous non-homologous end joining (NHEJ) repair mechanisms during blastic transformation in CML is indicated by abundant co-localization of γH2AX/53BP1 foci, while a decline of the DDR is suggested by defective expression of (p-)ATM and (p-)CHK2. In summary, our data provide evidence for the accumulation of DNA damage in the course of CML and suggest ongoing DNA damage, erroneous NHEJ repair mechanisms, and alterations in the DDR as critical mediators of blastic transformation in CML.

Case Report of acute myeloid leukemia with “WT1, ATRX, CEBPA, CSMD1, IKZF1, and LRP1B mutation and translocation between chromosome 1 and 19” developing from Philadelphia-negative chronic myeloid leukemia after TKI therapy

Rationale:The success of tyrosine kinase inhibitor (TKI) therapy has greatly prolonged the survival time of patients with chronic myeloid leukemia (CML), harboring the characteristic Philadelphia (Ph) chromosome. However, a fraction of patients, achieving complete cytogenetic response after TKI therapy, develop a myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) with additional clonal chromosomal abnormalities in Philadelphia-negative cells (CCA/Ph–).Patient concerns:A 56-year-old woman with AML, developing from Philadelphia-negative CML after TKI therapy. She showed 6 kinds of somatic variants—CEBPA, ATRX, WT1, CSMD1, IKZF1, and LRP1B mutation after diagnosed as AML.Diagnosis:The patient was diagnosed with chronic phase CML that developed to AML after achieving durable complete cytogenetic response (CCR) and major molecular response (MMR).Interventions:The patient was treated with TKI therapy at the period of CML. When diagnosed with AML, she received induction chemotherapy regimens, consolidation therapy, and allogeneic hematopoietic stem cell transplantation subsequently.Outcomes:The patient has been CCR and MMR for nearly 4 years, and has achieved complete remission after intervention related to AML. She is now preparing for allogeneic hematopoietic stem cell transplantation.Lessons:These rare occurrences highlight the importance of exploring the relevant pathogenesis of AML developing from CML after TKI therapy. In addition to monitoring molecular changes in the course of CML, cytogenetic analysis, or next-generation sequencing of CML patients should be performed.

Treatment-free remission in patients with chronic myeloid leukemia: literature review

Tyrosine kinase inhibitors have radically changed the course of chronic myeloid leukemia, significantly increasing survival and reducing the risk of disease progression. Nearly 50–70 % of patients achieve a consistently low or undetectable level of minimal residual disease – a deep molecular response. The long-term tyrosine kinase inhibitors treatment in about one-third of patients is accompanied by toxicity which impairs the quality of life. Therefore, the safe treatment discontinuation is relevant. The results of clinical trials have shown 40-60% possibility of maintaining treatment-free remission in patients with long-term deep molecular respons; however, all patients with molecular relapse regain molecular remission after the resumption of tyrosine kinase inhibitors therapy. Currently, clinical and biological factors associated with maintaining treatment-free remission are being studied. It is assumed that cessation of tyrosine kinase inhibitors therapy can improve the quality of life, but approximately 30 % of patients are reporting musculoskeletal pain – so called “withdrawal syndrome” – that begins or worsens after stopping tyrosine kinase inhibitors therapy. The mechanisms for the development of this phenomenon are currently unclear. Thus, many aspects concerning treatment-free remission require to be studied, which determines the importance of clinical trials in this area.

The Evolution of Genetic Aberrations in CML Patients Harboring a Ph-Negative Clone: A 6-Year Follow-up Study of 52 Patients

▪Background: Clonal chromosome aberrations in Philadelphia chromosome-negative metaphases (CCA/Ph-) occur in a subset of chronic myeloid leukemia (CML) patients. A shorter survival was reported for “non -Y” CCA/Ph- cases (Issa et al. Blood 2017). Besides -Y, the most frequent CCA/Ph- is +8, but a broad spectrum of other abnormalities can be found, including 7q-/-7, which is a typical aberration of myelodysplastic syndromes (MDS).In previous analyses we had shown an increased number of molecular genetic aberrations in CCA/Ph- compared to non-CCA/Ph- patients (Schnittger et al. ASH 2013, 2014). However, the clinical impact and the evolution of the mutation pattern is largely unknown. Here we extended follow-up and genetic characterization of the initial CCA/Ph- cohort.Aim:To determine the pattern of molecular mutations and their evolutionTo determine if mutations are part of the Ph+ or Ph- clonePatients and Methods: We included 52 CCA/Ph- patients (female: 25; male 27), with a median age of 58 [33-81] years, and a median BCR-ABL1/ABL1 ratio of 4.322% [0-58.088%] (N.A. for 4 pts.) at the time of initial CCA/Ph- detection. The following CCA/Ph- were present: trisomy 8 (n=26), other trisomies (n=4), -Y (n=7), del(7q)/-7 (n=4), others (n=7), two CCA/Ph- (n=4). We performed sequencing of myeloid gene panels on follow-up samples (1 to 3 per patient) on Illumina's MiSeq and NextSeq instruments (library preparation: 29-gene panel Thunderstorm RainDance [Lexington, MA] or 28-gene panel TruSeq [Illumina, San Diego, CA]). Data was analyzed with SeqNext (JSI Medical Systems, Kippenheim, Germany). Detected mutations were monitored on additional time points to determine variant allele frequency (VAF: mutated/all reads) development. A reference cohort of 47 patients with no sign of CCA/Ph- after MMR achievement was presented as part of our initial study (Schnittger et al. ASH 2014).Results:Cytogenetic monitoring was available over a median period of 31 [0-126] months for the CCA/Ph- and 26 [12-85] months for the reference cohort. Of the CCA/Ph- patients, 5/52 (10%) acquired additional typical aberrations as CCA/Ph- clone (incl. one -7), while in the reference cohort only one of 47 (2%) patients developed a -Y clone (n.s.).On the molecular level, we conducted a median follow-up of 72 [9-150] months for the CCA/Ph- cohort (mutations and BCR-ABL1/ABL1 ratio). Following the CCA/Ph- detection, somatic mutations were found in 30/52 (58%) patients (up to 4 per patient): ASXL1 (n=13), DNMT3A (n=10), TET2 (n=6), NRAS (n=3), RUNX1 (n=3), non-recurrent (n=8).The VAF of 7 mutations was strongly correlated to the BCR-ABL1 ratio and thus most likely present in the Ph+ clone. Mutations in ASXL1 were present in the Ph+ clone in five patients, of whom four never reached MMR, while 6/8 patients with ASXL1 mutations in Ph-independent clones achieved MMR under first- or second-line TKI therapy.Molecular genetic aberrations in Ph- cells were found in 23/52 (42%) CCA/Ph- patients, but only in 2 of 47 (4%) cases of the non-CCA/Ph- cohort (p<0.001). Importantly, in the reference cohort only TET2 and DNMT3A mutations were identified, which is the typical pattern in age related clonal hematopoiesis (ARCH) and also found in older individuals without a hematological malignancy. In the CCA/Ph- cohort, eight of 23 (35%) showed only TET2 or DNMT3A mutations. However, a highly predictive mutation signature for development of a myeloid malignancy (according to Malcovati et al. Blood 2017) was found in 8/23 (35%). In addition, of three NRAS positive CCA/Ph- cases, one was diagnosed with MDS/MPN overlap (also CALR positive) and two developed s-AML during the follow-up period and the NRAS VAF had increased to ≥35% at our last monitoring time point.Conclusions:ASXL1 mutations can occur in the Ph- as well as in the Ph+ clone and are associated with a poor TKI response, if present in the Ph+ clone.Molecular mutations are significantly more frequent in CCA/Ph- than in non-CCA/Ph-.While the mutation pattern in non-CCA/Ph- resembles ARCH, the spectrum in CCA/Ph- includes a higher risk pattern for development of a myeloid malignancy.Further prospective studies are required to evaluate the clinical impact of mutations acquired during the course of CML in order to determine which mutation pattern is related to a higher incidence of secondary myeloid malignancies. DisclosuresBaer:MLL Munich Leukemia Laboratory: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

The HLA Ligandome Landscape of Chronic Myeloid Leukemia Delineates Novel T-Cell Epitopes for Immunotherapy

Chronic myeloid leukemia (CML) is characterized by the translocation t(9;22), which leads to the formation of the BCR-ABL fusion transcript. Several approved tyrosine kinase inhibitors (TKIs) target the resulting fusion protein, leading to an improved prognosis of CML patients. Currently, the main treatment goal is the achievement of a deep molecular response (MR), in which TKI therapy can be terminated. Several studies provide evidence that immunological control plays a major role for the course of CML and contributes to the achievement of deep MR in CML patients under TKI treatment (CMLTKI). This implies that reinforcing these immune responses might sustain long-term TKI-free survival or even cure for CML patients. Besides unspecific immunotherapy, such as interferon or immune checkpoint blocking antibodies, a more specific and minor side effect targeting of CML cells might be achieved by antigen-specific immunotherapy approaches. The prerequisite for such strategies is the identification of T-cell targets represented by tumor-associated human leukocyte antigen (HLA)-presented peptides on malignant cells.In this study, we used a mass spectrometry-based approach to identify naturally presented, CML-associated peptides in primary CML samples (HLA class I, n=21, 11,945 peptides, 5,478 source proteins; class II, n=20, 5,991 peptides, 1,302 proteins). Comparative HLA peptidome profiling using a comprehensive dataset of various benign tissues (e.g. blood, bone marrow, spleen, and lung) revealed frequently presented and strictly CML-associated antigens. In detail, the benign tissue dataset comprises hematological benign samples (class I, n=108, 51,233 peptides, 11,437 proteins; class II, n=88, 42,753 peptides, 4,877 proteins) and non-hematological benign tissues (28 tissues, n=166; class I, 128,590 peptides, 16,405 proteins; class II, 143,652 peptides, 13,410 proteins). We identified 50 CML-associated, HLA class I-restricted peptides with HLA allotype adjusted representation frequencies of ≥38% presented on HLA-A*02, -A*03, -A*11, and -B*07. HLA class II comparative profiling delineated 36 peptides exclusively and frequently presented in the HLA peptidome of ≥20% analyzed CML patients.For immunological characterization, we selected 8 HLA class I- and 6 class II-restricted highly CML-associated antigens. These peptides were analyzed in IFNγ ELISPOT assays using PBMCs from CMLTKI patients and healthy volunteers (HVs). Peptide-specific immune recognition was detected for 1/8 (13%) HLA class I peptides in 2/17 (12%) of CMLTKI patients. We hypothesized that this weak immune response might be due to an impaired CD8+ T cell function that reportedly is caused by TKI treatment. Thus, we compared T-cell responses against viral epitopes in IFNγ ELISPOT assays of CMLTKI patients with that of HVs and chronic lymphocytic leukemia (CLL) patients: in line with our hypothesis, we observed significantly reduced IFNγ release of T cells from CMLTKI patients compared to HVs and CLL patients (p<0.001), whereas CD8+ T-cell counts were not reduced. In contrast, no reduced IFNγ production was observed for HLA class II-restricted viral epitopes. These results were confirmed by memory T-cell responses detected for 6/6 (100%) HLA class II CML-associated peptides with frequencies up to 24% (4/17) of analyzed CMLTKI patients.To assess the immunogenicity of all HLA class I peptides, we performed in vitro artificial antigen presenting cell-based priming experiments using CD8+ T cells of HVs and CML patients. Effective priming of T cells was observed for 8/8 CML-associated peptides in ≥70% of analyzed HVs with frequencies of 0.1-33.9% (mean 2.2%) of CD8+ peptide-specific T cells. Notably, peptide-specific CD8+ T cells with frequencies of 0.1-2.2% (mean 0.4%) could also be induced in samples of CMLTKI patients that had not displayed preexisting immune responses. For 6/8 peptides, we observed multifunctionality of peptide-specific T cells by IFNγ and TNF production as well as upregulation of the degranulation marker CD107a. Cytotoxicity assays with polyclonal peptide-specific effector T cells confirmed the capacity to induce antigen-specific lysis for 3/4 analyzed peptides.Taken together, we here identified novel, naturally presented, CML-associated antigens and validated them as promising targets for tailored T cell-based immunotherapeutic approaches for CML patients. DisclosuresSalih:Several patent applications: Patents & Royalties: e.g. EP3064507A1. Kowalewski:Immatics Biotechnologies GmbH: Employment. Schuster:Immatics Biotechnologies GmbH: Employment. Brümmendorf:Pfizer: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Janssen: Consultancy; Merck: Consultancy; Takeda: Consultancy. Niederwieser:Miltenyi: Speakers Bureau; Novartis: Research Funding.

Chronic Myeloid Leukemia: Beyond BCR-ABL1.

In this review, we emphasize up-to-date practical cytogenetic and molecular aspects of chronic myeloid leukemia (CML) and summarize current knowledge on tyrosine kinase inhibitor (TKI) resistance and treatment response monitoring of CML. The introduction of TKIs has changed the natural course of CML and markedly improved patient survival. Over the past decades, many research efforts were devoted to elucidating the leukemogenic mechanisms of BCR-ABL1 and developing novel TKIs. More recent studies have attempted to answer new questions that have emerged in the TKI era, such as the cytogenetic and molecular bases of treatment failure and disease progression, the clinical impact of genetic aberrations in Philadelphia chromosome (Ph)-positive and Ph-negative cells, and the biological significance of Ph secondarily acquired during therapy of other hematological neoplasms. Recent progresses in the understanding of the cytogenetic and molecular mechanisms underlying therapeutic failure and disease progression have improved the risk stratification of CML and will be helpful in the design of novel therapeutic strategies.

Cardiovascular events in chronic myeloid leukemia clinical trials. Is it time to reassess and report the events according to cardiology guidelines?

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of chronic myeloid leukemia (CML). Although these treatments have changed the natural course of CML and many other cancers, they may cause cardiovascular and/or metabolic complications. In this review, we discuss how overlooking the main drivers of cardiovascular events (CVEs) and lack of standard definitions for cardiovascular adverse events might have affected these event rates in CML trials. Methodological limitations that affect the available data are discussed, with an emphasis on the future direction of cardiovascular safety research in trials of investigational drugs in cancer treatment.

Impact of earlier versus later monitoring on disease progression and healthcare costs among patients with chronic myeloid leukemia in the United States

We evaluated the impact of molecular monitoring earlier as compared to later in the course of chronic myeloid leukemia (CML) on disease progression and healthcare costs in the real-world setting in the US. Patients with a diagnosis of CML were identified from the MarketScan claims databases (1 January 2006 to 30 June 2016). Multivariable regression analyses were used to control for differences in patient cohorts with earlier versus later monitoring. Of the 2730 CML patients in the study population, 60% (n = 1633) received earlier monitoring and 40% (n = 1097) received later monitoring only. After adjusting for differences in patient characteristics, patients with earlier monitoring had a lower likelihood of CML progression during the follow-up period (odds ratio: 0.72, confidence interval: 0.53–0.96; p = .03) and lower total healthcare costs ($6794 versus $9782 per-patient-per-month, p < .001) than patients with later monitoring. Patients who are monitored earlier in the course of CML may have better outcomes and lower total costs of care.

Cytogenetics-based risk prediction of blastic transformation of chronic myeloid leukemia in the era of TKI therapy.

The high fatality of patients with blast phase (BP) chronic myeloid leukemia (CML) necessitates identification of high-risk (HR) patients to prevent onset of BP. Here, we investigated the risk of BP based on additional chromosomal abnormality (ACA) profiles in a cohort of 2326 CML patients treated with tyrosine kinase inhibitors (TKIs). We examined the time intervals from initial diagnosis to ACA emergence (interval 1), from ACA emergence to onset of BP (interval 2), and survival after onset of BP (interval 3). Based on BP risk associated with each ACA, patients were stratified into intermediate-1, intermediate-2, and HR groups, with a median duration of interval 2 of unreached, 19.2 months, and 1.9 months, respectively. There was no difference in durations of intervals 1 or 3 among 3 groups. Including patients without ACAs who formed the standard-risk group, the overall 5-year cumulative probability of BP was 9.8%, 28.0%, 41.7%, and 67.4% for these 4 groups, respectively. The pre-BP disease course in those who developed BP was similar regardless of cytogenetic alterations, and 84.4% of BP patients developed BP within the first 5 years of diagnosis. In summary, interval 2 is the predominant determinant of BP risk and patient outcome. By prolonging the duration of interval 2, TKI therapy mitigates BP risk associated with low-risk ACAs or no ACAs but does not alter the natural course of CML with HR ACAs. Thus, we have identified a group of patients who have HR of BP and may benefit from timely alternative treatment to prevent onset of BP.

PIM-1 kinase inhibitor SMI-4a exerts antitumor effects in chronic myeloid leukemia cells by enhancing the activity of glycogen synthase kinase 3β.

The development of targeted tyrosine kinase inhibitors (TKIs) has succeeded in altering the course of chronic myeloid leukemia (CML). However, a number of patients have failed to respond or experienced disease relapse following TKI treatment. Proviral integration site for moloney murine leukemia virus-1 (PIM-1) is a serine/threonine kinase that participates in regulating apoptosis, cell cycle, signal transduction and transcriptional pathways, which are associated with tumor progression, and poor prognosis. SMI-4a is a selective PIM-1 kinase inhibitor that inhibits PIM-1 kinase activity in vivo and in vitro. The present study aimed to explore the mechanism underlying the antitumor effect of SMI-4a in K562 and imatinib-resistant K562 (K562/G) cell lines. It was demonstrated that SMI-4a inhibited the proliferation of K562 and K562/G cells using a WST-8 assay. The Annexin V-propidium iodide assay demonstrated that SMI-4a induced apoptosis of K562 and K562/G cells in a dose-, and time-dependent manner. Furthermore, Hoechst 33342 staining was used to verify the apoptosis rate. The clone formation assay revealed that SMI-4a significantly inhibited the colony formation capacity of K562 and K562/G cells. Western blot analysis demonstrated that SMI-4a decreased phosphorylated (p)-Ser9-glycogen synthase kinase (GSK) 3β/pGSK3β and inhibited the translocation of β-catenin. In addition, the downstream gene expression of apoptosis regulator Bax and poly(ADP-ribose) polymerase-1 was upregulated, and apoptosis regulator Bcl-2 and Myc proto-oncogene protein expression levels were downregulated. Immunofluorescence results demonstrated changes in the expression level of β-catenin in the plasma and nucleus. The results of the present study suggest that SMI-4a is an effective drug to use in combination with current chemotherapeutics for the treatment of imatinib-resistant CML.

Decreased calpain activity in chronic myeloid leukemia impairs apoptosis by increasing survivin in myeloid progenitors and xiap1 in differentiating granulocytes.

Chronic Myeloid Leukemia (CML) is characterized by translocations between chromosomes 9 and 22, resulting in expression of Bcr-abl oncogenes. Although the clinical course of CML was revolutionized by development of Bcr-abl-directed tyrosine kinase inhibitors (TKIs), CML is not cured by these agents. Specifically, the majority of subjects relapsed in clinical trials attempting TKI discontinuation, suggesting persistence of leukemia stem cells (LSCs) even in molecular remission. Identifying mechanisms of CML-LSC persistence may suggest rationale therapeutic targets to augment TKI efficacy and lead to cure. Apoptosis resistance is one proposed mechanism. In prior studies, we identified increased expression of Growth Arrest Specific 2 (Gas2; a Calpain inhibitor) in Bcr-abl+ bone marrow progenitor cells. A number of previously described Calpain substrates might influence apoptosis in CML, including βcatenin and the X-linked Inhibitor of Apoptosis Protein 1 (Xiap1). We previously found Gas2/Calpain dependent stabilization of βcatenin in CML, and increased expression of βcatenin target genes, including Survivin (also an IAP). In the current work, we investigate contributions of Survivin and Xiap1 to Fas-resistance in Bcr-abl+ bone marrow cells. Inhibitors of these proteins are currently in clinical trials for other malignancies, but a role for either IAP in CML-LSC persistence is unknown.

Role of Shelterin Complex and Alternative Telomere Lengthening in Genomic Instability and Disease Progression in Chronic Myeloid Leukemia

Genomic instability has many sources, among others, shortening of telomeres, nucleoprotein complexes located at the ends of chromosomes. Tumor cells have aberrant mechanisms of telomere maintenance: their telomeres are shortened, no longer preventing chromosome end-to-end fusion and recombination, but frequently not short enough to lead to cell senescence. Both telomerase and shelterin complexes are involved in telomere homeostasis. Reduction in the telomere length is considered as one of the features of chronic myeloid leukemia (CML) similar to other human malignancies and telomere shortening is correlated with disease progression from the chronic phase (CML-CP) to the blastic phase (CML-BP)1. However, recent report shows that shorter telomeres can actually be detected in patients who discontinued imatinib and are in treatment-free remission as compared to those who relapsed2. Therefore, there is no agreement on the telomere length dynamics in CML evolution. Moreover, the precise role of telomere-associated proteins, including shelterin complex in BCR-ABL1-mediated genomic instability in CML progression and resistance to TKIs, is not fully elucidated.Initially, we confirmed that the telomere shortening was positively correlated with CML progression (CML-BP in comparison to CML-CP). However, in CD34+ samples from CML-CP TKI-resistant patients in comparison to CML-CP patients, an increase in telomere length was observed. This suggests that shortening of telomeres in CML progression may have a biphasic scenario. This can be explained by alternative telomere lengthening (ALT) mechanisms, since no significant changes in the expression of subunits of the telomerase complex and its enzymatic activity were observed at different phases of the disease; enzymatic activity of telomerase was measured immunoenzymatically, while length of telomeres was determined by Southern blotting. Then we decided to analyze possible involvement of shelterin complex and of ALT mechanisms in CML progression. Importantly, expression of the three members of the shelterin complex, Protection Of Telomeres 1 (POT1), Repressor Activator Protein 1 (RAP1) and Tankyrase 1 (TNKS1) was significantly upregulated in CML-BP (10 samples) as compared to CML-CP (15 samples) and was also positively correlated with BCR-ABL1 expression. Moreover, as determined by TKI treatment of CD34+ CML-BP primary cells, expression of POT1 was BCR-ABL1-dependent. No significant changes were observed in the expression of other members of the shelterin complex, namely TINT1-PTOP-PIP1 (TPP1), TRF1 interactor 2 (TIN2) and Tankyrase 2 (TNKS2). Also telomere repeat-binding factor 1 and 2 (TRF1 and TRF2), which are responsible for anchoring shelterin complex to the double stranded telomeric repeats remain stable in the course of the disease. Expression of subunits of telomerase and shelterin complexes was examined by RT-qPCR and Western blotting. This was confirmed in K562 and K562 imatinib-resistant cell line model.Somatic mutations in POT1 have been recently described in human tumors including chronic lymphocytic leukemia (CLL). In CLL, mutations in POT1 affect telomere stability and are associated with shorter survival in patients receiving chemotherapy as a frontline treatment. We have screened our NGS data from targeted sequencing in a cohort of patients who progressed to CML-BP (paired CP and BP samples, n=10 and BP samples, n=9) but we did not detect any somatic mutations in POT1. This is in accordance with our data on POT1 upregulated expression and suggests that dysregulation of shelterin complex during progression of CML differs significantly from CLL.In conclusion, we present the first comprehensive analysis of the expression of all members of the shelterin complex in the course of CML. We postulate that abnormal expression of selected members such as POT1, RAP1 and TNKS1 may be responsible for the aberrant telomere maintenance mechanisms in CML cells and may play an important role in genomic instability associated with CML progression.

Chronic Myeloid Leukemia in the Era of Tyrosine Kinase Inhibitors: An Evolving Paradigm of Molecularly Targeted Therapy.

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm, characterized by the unrestrained expansion of pluripotent hematopoietic stem cells. CML was the first malignancy in which a unique chromosomal abnormality was identified and a pathophysiologic association was suggested. The hallmark of CML is a reciprocal chromosomal translocation between the long arms of chromosomes 9 and 22, t(9; 22)(q34; q11), creating a derivative 9q+ and a shortened 22q-. The latter, known as the Philadelphia (Ph) chromosome, harbors the breakpoint cluster region-abelson (BCR-ABL) fusion gene, encoding the constitutively active BCR-ABL tyrosine kinase that is necessary and sufficient for initiating CML. The successful implementation of tyrosine kinase inhibitors (TKIs) for the treatment of CML remains a flagship for molecularly targeted therapy in cancer. TKIs have changed the clinical course of CML; however, some patients nonetheless demonstrate primary or secondary resistance to such therapy and require an alternative therapeutic strategy. Therefore, the assessment of early response to treatment with TKIs has become an important tool in the clinical monitoring of CML patients. Although mutations in the BCR-ABL have proven to be the most prominent mechanism of resistance to TKIs, other mechanisms-either rendering the leukemic cells still dependent on BCR-ABL activity or supporting oncogenic properties of the leukemic cells independent of BCR-ABL signaling-have been identified. This article provides an overview of the current understanding of CML pathogenesis; recommendations for diagnostic tools, treatment strategies, and management guidelines; and highlights the BCR-ABL-dependent and -independent mechanisms that contribute to the development of resistance to TKIs.

Adjunctive Chinese Herbal Medicine therapy improves survival of patients with chronic myeloid leukemia: a nationwide population-based cohort study.

Despite good clinical results of current drugs, a good reason still exists to search for additional therapies for the management of Chronic Myeloid Leukemia (CML). Chinese Herbal Medicine (CHM) has thus far been overlooked by researchers and no data exists on the subject. We studied the impact of adjunctive CHM on the disease course of CML, using mortality as the major outcome measurement. We used the Taiwanese National Health Insurance Research Database to perform a nationwide population‐based cohort study. Our study included CML patients diagnosed between 2000 and 2010. We matched groups according to age, sex, Charlson Comorbidity Index (CCI) score and use of imatinib, and compared the Hazard Ratios (HR) of CHM group and non‐CHM users, as well as characterized trends of prescriptions used for treating CML. 1371 patients were diagnosed with CML in the years examined, of which 466 were included in to this study. We found that the HR of CHM group was significantly lower compared to non‐CHM groups (0.32, 95% CI 0.22–0.48, P < 0.0001). We also established that this association between reduced HR was dose‐dependent, and the longer CHM users received prescriptions, the lower the HR (P < 0.01). We also analyzed the most commonly used herbal products as well as the HR associated to their use, thus providing future research candidates. Our results supply a strong reason to assume that when administered by properly trained physicians, CHM may have a substantial positive impact on the management of CML.

Exploring the Significance of TP53, ABCB1 and GST Polymorphisms on Susceptibility and Pharmacogenetics in Argentinian Patients with Chronic Myeloid Leukemia

Chronic myeloid leukemia (CML) is specifically associated with the t(9;22)(q34;q11) reciprocal translocation giving rise to the Philadelphia chromosome and the subsequent formation of the BCR/ABL1 fusion gene, encoding a constitutively active tyrosine kinase. Advances in targeted therapies in chronic phase CML, notably the use of tyrosine kinase inhibitors (TKIs) such as imatinib mesylate (IM), have achieved successful treatment outcomes. However, some patients fail to achieve optimal response, and a substantial proportion of patients develop resistance to IM, which is frequently associated with mutations in the ABL kinase domain. Although BCR/ABL1 fusion oncogene is a key molecular marker involved in the pathogenesis and the clinical course of CML, molecular or cellular events that initiate leukemogenesis or drive translocation of the BCR/ABL1 genes are incompletely understood and little is known about individual susceptibility to this disease. Moreover, it is still unclear whether BCR/ABL1 oncoprotein alone is sufficient to explain the full range of clinical responses to ITKs. There is mounting evidence that genetic factors may play an important role in susceptibility to CML and variability in drug responsiveness. Polymorphic variants of several genes are linked to variations in expression, function, drug disposition and drug response and are potential factors accounting for susceptibility to complex diseases or drug resistance as they can uniquely influence the quality and quantity of gene product. Association studies have been performed to identify genetic variants associated with CML susceptibility and progression, but data are lacking for Argentina. In the present study, we determined the distribution of polymorphisms on TP53 tumor suppressor gene, drug transporter (ABCB1) and drug-metabolizing (glutathione-S-transferases, GSTs) genes to identify markers of susceptibility and pharmacogenetic response in Argentinian patients with CML.Genomic DNA samples from peripheral blood of 141 patients (69 females/72 males, median age 50.8 ± 1.3 years,) treated with IM and 141 age and sex matched healthy controls were evaluated. IM therapy failure was defined by cytogenetics and qRT-PCR in 2 consecutive studies, finding 76 cases that fail treatment. All individuals provided their informed consent according to institutional guidelines and the study was approved by the Ethics Committee of our Institution. GSTM1 and GSTT1 gene deletion polymorphisms and single nucleotide polymorphisms (SNPs) in GSTP1 (313A> G), TP53 (215C> G) and ABCB1 (3435C> T, 1236 C> T and 2677G>T/A) were determined using PCR-based methods. BCR/ABL1 transcript level was analyzed using RT-PCR and ABL1 mutations were identified by RT-PCR and sequencing. Comparison of genotypes between patients and controls as well as regarding clinical parameters was performed by logistic regression. The Kaplan-Meier curves were analyzed using the log-rank test. The level of significance was p <0.05. The case/control association analysis highlighted that carriers of TP53 CC+CG genotypes influence CML susceptibility (p=0.007; OR: 4.5; CI: 1.5-13.3), but no other markers were significantly involved. Next, the pharmacogenetic analysis was performed associating different genotypes with molecular response and treatment failure. We determined that patients carrying GSTM1 -present genotype did not reached major molecular response (p=0.038; OR: 2.9; CI: 1.16-7.4). In addition, average time to treatment change was significantly lower for carriers of the following genotypes: ABCB1 1236TT (23 months), ABCB1 3435TT (13.6 months) and GSTM1 -present (53 months), respect to patients with other variants (p=0.017; p=0.0046 and p=0.04, respectively). Finally, patients with TP53 CC+CG polymorphisms had an increased risk of progression (p=0.039) and lower overall survival (p=0.017). These results indicate that TP53 genotype may represent a genetic cofactor that influences susceptibility to CML and genotypic variations of TP53, ABCB1 and GSTM1 may modulate the response to imatinib. DisclosuresMoiraghi:Bristol Myers Squibb: Speakers Bureau; Novartis: Speakers Bureau. Bengio:Novartis: Speakers Bureau; Bristol Myers Squibb: Speakers Bureau.